Working fluid compositions

ABSTRACT

The present invention relates to a composition suitable to be used as working fluid, said composition being in the form of a solution and comprising at least one (per)fluoropolyether polymer [polymer (P)] and at least one amorphous polymer [polymer (F)].

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European application No. 17164462.8filed on 3 Apr. 2017, the whole content of this application beingincorporated herein by reference for all purposes.

TECHNICAL FIELD

The present invention relates to a composition suitable to be used asworking fluid.

BACKGROUND ART

Working fluids are gases or liquids that, when pressurized, actuate amachine. Typical examples include steam in a steam engine, air in a hotair engine and hydraulic fluid in a hydraulic motor or hydrauliccylinder. More generally, in a thermodynamic system, the working fluidis a liquid or gas that absorbs or transmits energy.

The working fluid properties are essential for the full description ofthermodynamic systems. Among the large number of suitable physicalproperties, their viscosity is of particular importance for use inapplications such as hydrodynamic coupling, notably viscous couplings,and damping.

Working fluids that are suitable for the abovementioned applications andcomprise organopolysiloxane as the base oil have been disclosed forexample in U.S. Pat. No. 4,959,166 (COSMO OIL CP., LTD. ET AL.), EP0397507 A (TONEN CORPORATION) and EP 0599251 A (COSMO OIL COMPANY, LTD.ET AL.).

More recently, WO 2016/150941 (SOLVAY SPECIALTY POLYMERS ITALY S.P.A.)disclosed a method for counteract vibrations and/or shocks in a device,wherein the method comprises:

providing an apparatus comprising a damper device, said damper devicecomprising at least one (per)fluoropolyether copolymer [polymer (P)]having a viscosity higher than 2,000 mm/s and comprising recurring unitsderived from (per)fluoropolyether and recurring units derived from atleast one olefin, the viscosity being measured at 20° C. according tostandard method ASTM D445, or with a dynamical mechanical spectrometerAnton Paar MCR 502 rheometer equipped with parallel plates 25 mm, at 1rad/s and at 25° C.

This application teaches to provide a fluid suitable for use in a damperdevice, wherein the fluid is obtained by reacting a (per)fluoropolyetherpolymer and at least one olefin.

Compositions comprising a (per)fluoropolyether (PFPE) polymer as baseoil and at least one perfluoropolymer, typically in the form ofsuspensions or dispersions, have been disclosed in the art.

For example, U.S. Pat. No. 6,100,325 (AUSIMONT S.P.A.) discloses acomposition in the form of dispersion, which comprises 0.1-30 wt. % of apolytetrafluoroethylene or of tetrafluoroethylene (TFE) copolymers,50-90 wt. % of a fluorinated liquid, 0.01-5 wt. % of a surfactant and apolar solvent (water and/or alcohol) in an amount complement to 100 wt.%. U.S. Pat. No. 6,025,307 (AUSIMONT S.P.A.) discloses a fluorinatedgrease, in the form of dispersions, comprising 15-50 wt. % ofpolytetrafluoroethylene or tetrafluoroethylene copolymers, 30-84.5 wt. %of perfluoropolyether oil having a viscosity comprised between 20 and4000 cSt at 20° C.; 0.5-10 wt. % of surfactant or dispersant havingperfluoropolyether or perfluoroalkylic chain; and optionally ananti-corrosion or anti-wear additive.

Lubricant compositions comprising a (per)fluoropolyether (PFPE) polymercharacterized by high viscosity, for example in the form of paste, havebeen also disclosed in the art.

U.S. Pat. No. 5,032,302 (EXFLUOR RESEARCH CORPORATION) discloses alubricant comprising perfluoropolyether oils containingperfluoropolyether solids as fillers, which can be prepared by mixingthe perfluoropolyether solid and the perfluoropolyether oil. Thesecompositions are said to be stable and to do not exhibit phaseseparation because the oil and the solid, being of the same chemicalcomposition, are extremely compatible.

Also, JP H0673370 (NTN CORP.) discloses a damper sealant that is put incontact with a slidable member in order to prevent the leakage of anenergy-absorbing fluid in a bumper or damper and is made of alubricating rubber composition comprising (A) a thermoplasticfluororesin, (B) a fluororubber and (C) low molecularfluorine-containing polymer. In the description, as examples ofcomponent (C) the following are mentioned: tetrafluoroethylene polymer,fluoropolyether and polyfluoroalkyl. The fluoropolyethers have notablythe following structures:

CF₃O(C₂F₄)_(m)(CF₂O)_(n)—CF₃

CF₃O(CF₂CF(CF₃)O)_(m)(CF₂O)_(n)—CF₃

CF₃O(CF(CF₃)CF₂O)_(m)(CF₂O)_(n)—CF₃.

SUMMARY OF INVENTION

The Applicant perceived that in working fluid comprising two differentphases (typically a solid phase dispersed or suspended into a liquidphase), phase separation can occur when the working fluid is used inharsh conditions.

Also, the Applicant perceived that the highly viscous silicone oilscurrently used as damping fluids suffer from some disadvantages, such assensitivity to acids, bases and moisture and in particular thermalinstability. Indeed, as a result of prolonged exposure to hightemperatures (200° C. or even higher) the highly viscous silicone oilsgradually harden over time, until they become inoperable and must bereplaced. Also, the Applicant noted that the thermal instability of thehighly viscous silicone oils becomes more evident as the viscosity ofthe silicone oil increases.

Thus, the Applicant faced the problem to provide a composition intendedfor use as working fluid in several applications. To this aim, theApplicant faced the problem of providing a composition that can beprepared via a simple process, such that a wide range of viscosity canbe provided depending on the final intended use.

The Applicant has surprisingly found that a composition in the form of asolution can be obtained by contacting at least one (per)fluoropolyetherpolymer and at least one amorphous polymer.

Advantageously, the Applicant found that the composition of the presentinvention is able to retain its viscous properties over a wide range oftemperatures, without showing degradation even after use for long timein a harsh environment.

Thus, in a first aspect, the present invention relates to a composition[composition (C)] comprising at least one (per)fluoropolyether polymer[polymer (P)] and at least one amorphous polymer [polymer (F)], whereinsaid composition (C) is in the form of a solution.

Advantageously, said polymer (F) is selected in the group consisting ofamorphous polymers characterized by a glass transition temperature(T_(g)) measured according to ASTM D3418, in the range from −100° C. to250° C. It will be apparent to those skilled in the art that saidpolymer (F), being amorphous, does not show a melting temperature(T_(m)) when analysed by thermal analysis following ASTM D3418.

As mentioned above, the Applicant noted that composition (C) accordingto the present invention can be prepared having a wide range ofviscosity, which can be modulated on the basis of the final use forwhich said composition (C) is intended.

Advantageously, said composition (C) is characterized by a viscosity inthe range from 100 mm²/s and up to 2,000,000 mm²/s (measured at 20° C.according to standard methods, such as ASTM D445, or with a dynamicalmechanical spectrometer Anton Paar MCR 502 rheometer equipped withparallel plates 25 mm, at 1 rad/s and at 25° C.).

As a consequence, said composition (C) can be used as working fluid inseveral applications, with the advantage that phase separation cannotoccur in a homogeneous solution, even after exposure at hightemperatures.

DESCRIPTION OF EMBODIMENTS

For the purpose of the present description and of the following claims:

-   -   the use of parentheses around symbols or numbers identifying the        formulae, for example in expressions like “polymer (P)”, etc.,        has the mere purpose of better distinguishing the symbol or        number from the rest of the text and, hence, said parenthesis        can also be omitted;    -   the acronym “PFPE” stands for “(per)fluoropolyether” and, when        used as substantive, is intended to mean either the singular or        the plural from, depending on the context;    -   the prefix “(per)” in the term “(per)fluoropolyether” or in the        term (per)fluoropolymer is intended to indicate that the        polyether or the fluoropolymer can be fully or partially        fluorinated;    -   the term “solution” is intended to indicate a homogeneous        mixture composed of at least two components, i.e. at least one        solute (preferably an amorphous polymer) that is dissolved in a        solvent (preferably the (per)fluoropolyether polymer);    -   the term “homogeneous” is intended to indicate that the mixture        has the same proportions of its components throughout a given        amount of the same;    -   the term “amorphous” is intended to indicate polymer(s) that,        when subjected to Differential Scanning calorimetry (DSC)        according to ASTM D3418, show(s) a glass transition (T_(g)) but        does not show a melting transition (T_(m)).

Preferably, said polymer (P) is a (per)fluoropolyether polymercomprising a (per)fluoropolyether chain [chain (R_(pf))] of formula:

—(CFX)_(a)O(R_(f))(CFX′)_(b)—

wherein

a and b, equal or different from each other, are equal to or higher than1, preferably from 1 to 10, more preferably from 1 to 3;

X and X′, equal or different from each other, are —F or —CF₃, providedthat when a and/or b are higher than 1, X and X′ are —F;

(R_(f)) comprises, preferably consists of, repeating units R^(∘), saidrepeating units being independently selected from the group consistingof:

(i) ˜CFXO—, wherein X is F or CF₃;

(ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is For CF₃, with the proviso that at least one of X is F;

(iii) —(CF₂)_(j)—CFZ—O— wherein j is an integer from 0 to 3 and Z is agroup of general formula —O—R_((f-a))-T, wherein R_((f-a)) is afluoropolyoxyalkene chain comprising a number of repeating units from 0to 10, said recurring units being chosen among the following: —CFXO—,—CF₂CFXO—, with each of X being independently F or CF₃ and T being aC₁-C₃ perfluoroalkyl group.

Preferably, said chain (R_(f)) is selected from chains of formula:

—[(CF₂CF₂O)_(b1)(CF₂O)_(b2)(CF(CF₃)O)_(b3)(CF₂CF(CF₃)O)_(b4)]—  (R_(f)-I)

wherein:

b1, b2, b3, b4, are independently integers ≥0 such that the numberaverage molecular weight is between 400 and 20,000, preferably between1,000 and 10,000; preferably b1 is 0, b2, b3, b4 are >0, with the ratiob4/(b2+b3) being ≥1;

—[(CF₂CF₂O)_(c1)(CF₂O)_(c2)(CF₂(CF₂)_(cw)CF₂O)_(c3)]—  (R_(f)-II)

wherein:

cw=1 or 2;

c1, c2, and c3 are independently integers ≥0 chosen so that the numberaverage molecular weight is between 400 and 20,000, preferably between1,000 and 10,000; preferably c1, c2 and c3 are all >0, with the ratioc3/(c1+c2) being generally lower than 0.2;

—[(CF₂CF(CF₃)O)_(d)]—  (R_(f)-III)

wherein:

d is an integer >0 such that the number average molecular weight isbetween 1,000 and 20,000, preferably between 400 and 10,000;

—[(CF₂O)_(c2)(CF₂(CF₂)_(cw)CF₂O)_(c3)]—  (R_(f)-IV)

wherein:

cw=1 or 2;

c2 and c3 are independently integers ≥0 chosen so that the numberaverage molecular weight is between 400 and 20,000, preferably between1,000 and 10,000; preferably the ratio c3/c2 is generally lower than0.2;

—[(CF₂CF₂C(Hal*)₂O)_(e1)—(CF₂CF₂CH₂O)_(e2)—(CF₂CF₂CH(Hal*)O)_(e3)]—  (R_(f)-V)

wherein:

-   -   Hal*, equal or different at each occurrence, is a halogen        selected from fluorine and chlorine atoms, preferably a fluorine        atom;    -   e1, e2, and e3, equal to or different from each other, are        independently integers ≥0 such that the (e1+e2+e3) sum is        comprised between 2 and 300.

Good results have been obtained when said chain (R_(f)) comprises atleast one recurring unit comprising 3 carbon atoms.

According to a particularly preferred embodiment, said chain (R_(f))complies with formulae (R_(f)-VI-a) to (R_(f)-VI-c):

—[(CF₂CF(CF₃)O)_(f1)—(CF₂O)_(f2)]—  (R_(f)-VI-a)

wherein

f1 and f2, are independently integers ≥0 such that the number averagemolecular weight is between 400 and 20,000, preferably between 1,000 and10,000; preferably both f1 and f2 are integers higher than 0, with theratio f1/f2 being 1, more preferably higher than 1;

—(CF(CF₃)CF₂O)_(f3)—  (R_(f)-VI-b)

wherein

f3 is an integer higher than 0, such that the number average molecularweight is between 400 and 20,000, preferably between 1,000 and 10,000;

—(CF₂CF₂CF₂O)_(f4)—  (R_(f)-VI-c)

wherein

f4 is an integer higher than 0, such that the number average molecularweight is between 400 and 20,000, preferably between 1,000 and 10,000.

According to a preferred embodiment, said chain (R_(pf)) has two chainends comprising perfluorooxyalkyl groups, more preferably comprisingfrom 1 to 3 carbon atoms.

Suitable polymers (P) are commercially available under the trade nameFomblin® from Solvay Specialty Polymers Italy S.p.A., Krytox® fromChemours Co., and Demnum® from Daikin Ind., Ltd.

Preferably, said polymer (F) is selected in the group comprising, morepreferably consisting of:

-   -   styrene polymers and co-polymers, such as polystyrene (PS),        acrylonitrile/butadiene/styrene (ABS), styrene/acrylonitrile        (SAN), styrene/acrylic (S/A), styrene/maleic anhydride (SMA);    -   vinyl polymers and co-polymers, such as polyvinylchloride (PVC)        and chlorinated polyvinylchloride (CPVC);    -   acrylic polymers and co-polymers, such as polymethylmethacrylate        (PMMA) and PVC/acrylic blends;    -   (per)fluoropolymers, more preferably perfluoropolymers;    -   polyesters, such as polyethylene terephthalate glycol-modified        (PETG) and polyarylate (PAR);    -   polyamideimide (PAI) and polyetherimide (PEI);    -   polyethers, such as polycarbonate (PC), polyphenylene oxide        blends (PPO);    -   sulphur containing polymers, such as polysulphone (PSF),        polyethersulfone (PES) and polyarylsulfone (PAS);    -   polyurethane (TPU), fluorinated polyurethane and acrylonitrile        polymers.

Good results have been obtained by selecting said polymer (F) amongperfluoropolymers.

In the present description and in the following claims:

-   -   the term “perfluoropolymer” is intended to indicate a polymer        consisting essentially of recurring units derived from at least        one perfluorinated monomer;    -   the expression “perfluorinated monomer” is intended to indicate        fully fluorinated monomers, which are free of hydrogen atoms;    -   the expression “consisting essentially of” is intended to        indicate that minor amounts of end chains, defects,        irregularities and monomer rearrangements are tolerated in the        perfluoropolymer;    -   the expression “at least one perfluorinated monomer” is intended        to indicate that the perfluoropolymer contains recurring units        derived from one or more perfluorinated monomers.

Suitable perfluoropolymers according to the present invention compriseat least one recurring units comprising at least one perfluorinatedmonomer selected in the group comprising, preferably, consisting of:

(A) cyclic monomers complying with one of the following formulae (A1) to(A3):

wherein each of R_(f4), R_(f5), R_(f6), equal of different each other,is independently a fluorine atom, a C₁-C₆ perfluoroalkyl group,optionally comprising one or more oxygen atom, e.g. —CF₃, —C₂F₅, —C₃F₇,—OCF₃, —OCF₂CF₂OCF₃;

wherein n is 1 or 2;

wherein n is 1 or 2;

(B) C₂-C₈ perfluoroolefins, such as tetrafluoroethylene (TFE) andhexafluoropropene (HFP);

(C) CF₂═CFOR_(f1), wherein R_(f1) is selected from:

(R_(f1)*) C₁-C₆ perfluoroalkyl group, such as —CF₃, —C₂F₅, —C₃F₇; or

(R_(f1)**) —CF₂O(CF₂)_(t)OR_(f2)

wherein t is an integer equal to 1 or 2 and R_(f2) is a linear orbranched C₁-C₆ perfluoroalkyl group, e.g. —CF₃, —C₂F₅, —C₃F₇; a cyclicC₅-C₆ perfluoroalkyl group, or a linear or branched C₁-C₁₂(per)fluorooxyalkyl group comprising one or more ether groups, such as—CF₂CF₂OCF₃ and —CF(CF₃)OCF₃.

According to a first preferred embodiment, said polymer (F) is acopolymer of tetrafluoroethylene (TFE), i.e. it comprises recurringunits derived from TFE and recurring units derived from at least oneperfluorinated monomer different from TFE [co-monomer (F)].

The term “copolymer” is intended to indicate also TFE terpolymer and TFEtetrapolymer, comprising recurring units derived from TFE and from twoand three perfluorinated monomers different from TFE, respectively.

According to a first variant of the first preferred embodiment, said atleast one co-monomer (F) is selected from the group consisting of:

wherein each of R_(f4), R_(f5), R_(f6), equal of different each other,is independently a fluorine atom, a C₁-C₆ perfluoroalkyl group,optionally comprising one or more oxygen atom, e.g. —CF₃, —C₂F₅, —C₃F₇,—OCF₃, —OCF₂CF₂OCF₃; more preferably, R_(f4) is —OCF₃ or F and R_(f5)and R_(f6) are both a fluorine atom or both a methyl group;

wherein n is 1 or 2;

wherein n is 1 or 2; and

-   -   combinations thereof.

According to this first variant, polymer (F) preferably comprises morethan 50% by moles, more preferably more than 75% by moles of recurringunits derived from said at least one co-monomer selected from those offormula (A1) to (A3) above.

According to this first variant, polymer (F) preferably comprises up to99% by moles, more preferably up to 95% by moles of recurring unitsderived from said at least one co-monomer selected from those of formula(A1) to (A3) above.

According to this first variant, polymer (F) preferably comprises from77% by moles to 95% by moles of recurring units derived from said atleast one co-monomer selected from those of formula (A1) to (A3) aboveand recurring units derived from TFE, such that the sum of thepercentages of recurring units from said monomer and from TFE is equalto 100% by moles.

According to a second variant of the first preferred embodiment, said atleast one co-monomer (F) is selected in the group consisting of:

(C) CF₂═CFOR_(f1), wherein R_(f1) is selected from:

-   -   (R_(f1)*) —CF₃, —C₂F₅, and —C₃F₇, namely,    -   perfluoromethylvinylether (PMVE of formula CF₂═CFOCF₃),    -   perfluoroethylvinylether (PEVE of formula CF₂═CFOC₂F₅),    -   perfluoropropylvinylether (PPVE of formula CF₂═CFOC₃F₇), and    -   combinations thereof;    -   (R_(f1)**) —CF₂OR_(f2),    -   wherein R_(f2) is a linear or branched C₁-C₆ perfluoroalkyl        group, cyclic C₅-C₆ perfluoroalkyl group, a linear or branched        C₂-C₆ perfluoroxyalkyl group; more preferably, R_(f2) is —CF₂CF₃        (MOVE1), —CF₂CF₂OCF₃ (MOVE2), —CF(CF₃)OCF₃ (MOVE2a) or —CF₃        (MOVE3); and        -   combinations thereof.

According to this second variant, polymer (F) preferably comprises morethan 5% by moles, more preferably more than 15% by moles of recurringunits derived from said at least one co-monomer selected from those offormula (C).

According to this second variant, polymer (F) preferably comprises up to50% by moles, more preferably up to 45% by moles of recurring unitsderived from said at least one co-monomer selected from those of formula(C) above.

According to this second variant, polymer (F) preferably comprises from15% by moles to 45% by moles of recurring units derived from said atleast one co-monomer selected from those of formula (C) above andrecurring units derived from TFE, such that the sum of the percentagesof recurring units from said co-monomer and from TFE is equal to 100% bymoles.

According to a second preferred embodiment, said polymer (F) is ahomopolymer, i.e. it essentially consists of recurring units of formula(A1)

wherein each of R_(f4), R_(f5), R_(f6), equal of different each other,are as defined above; more preferably, R_(f4) is —OCF₃ or F and R_(f5)and R_(f6) are both a fluorine atom or both a methyl group.

According to a third preferred embodiment, said polymer (F) is ahomopolymer or copolymer comprising recurring units of formula:

CF₂═CFO—CF₂O—CF₂CF₃ (MOVE1);  (C**i)

CF₂═CFO—CF₂O—CF₂CF₂OCF₃(MOVE2);  (C**ii)

CF₂═CFO—CF₂O—CF(CF₃)OCF₃(MOVE2a);  (C**iii)

CF₂═CFO—CF₂O—CF₃ (MOVE3);  (C**iv)

and combinations thereof.

Unexpected results have been obtained in the present invention selectingsaid polymer (F) from polymers commercially available under the tradename of HYFLON® AD, Tecnoflon® PFR-LT (both commercially available fromSolvay Specialty Polymers Italy S.p.A.), Teflon® AF (commerciallyavailable from Chemours Co.) and Cytop® (commercially available fromCytec Ind. Inc.).

Composition (C) can be prepared according to known techniques of theprior art. Preferably, the composition according to the presentinvention is prepared by solvent mixing or dry mixing.

According to a first preferred embodiment, at least one polymer (F) isdissolved in at least one solvent [solvent (S)], preferably a(per)fluorinated solvent, and mixed with a stirrer machine.

Said at least one solvent (S) is preferably selected from(per)fluoropolyethers having chemical formula different from thechemical formula of polymer (P) (such as, those commercially availablefrom Solvay Specialty Polymers Italy S.p.A. under the trade nameGalden®), perfuoroalkanes (such as, perfuorohexane, perfuoroheptane andthe like), hydrofluoroethers, and mixtures thereof.

Then, a heating step is performed at a temperature lower than thesolvent (S) boiling point. More preferably, said heating step isperformed at a temperature between 20 and 100° C. Even more preferably,said heating step is performed for at least 1 hour.

Then, a cooling step to room temperature is performed, thus obtaining acomposition [composition (C)] in the form of a solution comprising saidpolymer (F) and said at least one solvent (S).

Then, said composition (CA) and at least one polymer (P) are contacted,to form a composition [composition (CAA)] and a mixing step isperformed. Preferably, said mixing step is performed at roomtemperature, more preferably for about 1 hour. Then, said composition(CAA) is heated to remove said at least one solvent (S), preferably bytreatment under vacuum, to obtain the composition (C) according to thepresent invention.

According to a second preferred embodiment, at least one polymer (P) andat least one polymer (F) are first contacted and then mixed togetherwith a stirrer machine. Then, a heating step is performed, at atemperature of about 150-200° C., preferably for more than 1 hour, evenmore preferably from 2 to 5 hours.

Preferably, said composition (C) comprises at least one polymer (P) inan amount higher than 50 wt. % and up to 99.99 wt. %, more preferablyfrom 60 wt. % to about 99.95 wt. %, even more preferably from 70 to99.90 wt. % based on the total weight of said composition (C).

Preferably, said composition (C) comprises at least one polymer (F) inan amount of from 0.01 to less than 50 wt. %, more preferably from 0.05to 40 wt. %, even more preferably from 0.10 to 30 wt. % based on thetotal weight of said composition (C).

According to a particular preferred embodiment, said composition (C)comprises at least one polymer (F) in an amount of from 0.1 to 20 wt. %based on the total weight of said composition (C).

Composition (C) according to the invention has a viscosity in the rangefrom 100 mm²/s to 2,000,000 mm²/s—measured at 20° C. according tostandard methods, such as ASTM D445, or with a dynamical mechanicalspectrometer Anton Paar MCR 502 rheometer equipped with parallel plates25 mm, at 1 rad/s and at 25° C.

Compositions (C) according to the present invention can further compriseadditional ingredients, selected in the group comprising heat-resistanceimproving agents, anti-oxidant agents, anti-wear agents and the like.

Typically, each of the additional ingredients is added to thecomposition in an amount from 0.0001 wt. % and up to 5 wt. % based onthe total weight of composition (C).

Advantageously, composition (C) according to the present invention canbe used as hydraulic fluid in viscous couplings, shock absorbers, pumps,brake cylinders; damping media in speed regulators, fluid clutches(e.g., for fans), nautical and aero-nautical instruments,gyro-compasses, shock-absorbing struts, recording instruments, timeregulators, pneumatic valves, overload relays, sound pickups;lubricants; release agents

According to a preferred embodiment, composition (C) is used as workingfluid within a viscous coupling.

Viscous couplings are mechanical devices typically composed of ahousing, a hub and several tens of thin annular plates attached to eachof the housing and the hub. When composition (C) according to thisinvention is used, a viscous coupling is provided also comprising saidcomposition (C) within the housing.

According to a preferred embodiment, composition (C) is used as workingfluid within a damper device.

Suitable damper devices are selected in the group comprising dash pots;shock absorbers such as twin-tube or mono-tube shocks absorbers,positive sensitive damping (PSD) shock absorbers, acceleration sensitivedamping (ASD); rotary dampers; tuned mass dampers; viscous couplings;viscous fan clutches and torsional viscous dampers.

Typical apparatus wherein the damper devices can be used are selected inthe group comprising: mechanical or electric device for wheeled vehicles(such as suspensions installations, carburettors, internal combustiondevices, engines, transmissions, crankshafts), for work boats (such asengines), for aircrafts and spacecraft (such as aircraft carrier decks),for power transmission lines, for wind turbine, for consumer electronics(such as mobile phones and personal computers), for off-shore rig, foroil & gas distribution systems (such as pumps); compressors (such asreciprocating compressors for gas pipelines); devices for buildings andcivil structures (such as bridges, towers, elevated freeways).

According to another embodiment, the present invention relates to amethod for increasing the viscosity of at least one polymer (P) asdefined above, said method comprising contacting said at least onepolymer (P) with at least one polymer (F) as defined above.

Should the disclosure of any patents, patent applications, andpublications which are incorporated herein by reference conflict withthe description of the present application to the extent that it mayrender a term unclear, the present description shall take precedence.

The invention will be herein after illustrated in greater detail bymeans of the Examples contained in the following Experimental Section;the Examples are merely illustrative and are by no means to beinterpreted as limiting the scope of the invention.

EXAMPLES

Materials

Base oils 1 to 3, Polymers A to E and Galden®HT55 perfluoropolyetherpolymer were obtained from Solvay Specialty Polymers Italy S.p.A.

Base oil (P1): Fomblin®Y06 PFPE branched PFPE oil having the followingchemical formula:

CF₃O—[(CF₂CF(CF₃)O)_(m)—(CF₂O)_(n)]—CF₃

with m/n=40/1 and average molecular weight of about 1,800 Da.

Base oil (P2): Fomblin®YPL1500 PFPE branched PFPE oil having thefollowing chemical formula:

CF₃O—[(CF₂CF(CF₃)O)_(m)—(CF₂O)_(n)]—CF₃

with m/n=40/1 and average molecular weight of about 6,600 Da.

Base oil (P3): Fomblin® PFPE branched PFPE oil having the followingchemical formula:

CF₃O—[(CF₂CF(CF₃)O)_(m)—(CF₂O)_(n)]—CF₃

with m/n=40/1 and average molecular weight of about 8,500 Da.

Polymer (F^(A)): Tecnoflon® PFR LT

low temperature perfluoroelastomer

Polymer (F^(B)): Hyflon® AD 40L

amorphous perfluorinated copolymers of2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxide(TTD) andtetrafluoroethylene (TFE)

having glass transition temperature (measured according to ASTM D3418)of 95° C. and intrinsic viscosity (measured according to ASTM D2857) of0.40 dl/g at 30° C.

Polymer (F^(C)): Hyflon® AD 40H

amorphous perfluorinated copolymers of2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxide (TTD) andtetrafluoroethylene (TFE)

having glass transition temperature (measured according to ASTM D3418)of 95° C. and intrinsic viscosity (measured according to ASTM D2857) of1.3 dl/g at 30° C.

Polymer D: Algofon® L203

PTFE powder

Polymer E: Hylar® 5000

PVDF powder

Methods

The kinematic viscosity at a given temperature was determined accordingto ASTM D445 using a Cannon-Fenske capillary viscosimeter.

Viscosity index (VI) was determined according to ASTM D2270.

The compositions according to the invention were prepared according tothe following procedure.

Each of Polymer F^(A), F^(B) and F^(C) in the amount provided in thefollowing

Table was weighed and dissolved in a glass flask, with 40 g ofGalden®HT55 as solvent. The mixture was put under stirring at 40° C. forone hour. At the end of the stirring, the mixture was analysed by visualinspection. The solution was homogeneous.

Then, 98 g of Base Oil P3 were added and the mixture was heated to thesolvent reflux under stirring (700 rpm) for one hour. The solution thusobtained, which appeared clear and homogeneous, was heated up to 150° C.under vacuum in order to remove the solvent.

The final composition consisted of a single phase clear, viscous andsticky.

This compositions was submitted to further characterization andanalysis.

All the compositions according to the invention were prepared followingthe procedure described above, by using the Base Oils, the Polymersprovided in the following Table 1.

As comparison, Table 1 also shows the properties of each of the BaseOils.

TABLE 1 Amount of Temperature (° C.) Base Polymer 20 40 100 ViscosityExample Oil Polymer (% wt.) Kinematic viscosity (mm²/s) Index (VI) 1(*)P1 — — 63 24 3.6 70 2 P1 F^(A) 5 1503 480 36 113 3 P1 F^(B) 5 1880 49037 115 4(*) P2 — — 1500 420 40 144 5(*) P3 — — 2302 615 53.4 147 6 P3F^(B) 2 7435 1683 105 145 7 P3 F^(C)   0.5 5568 1354 93 149 8 P3 F^(C) 2117,264 20,095 655 188 (*)comparison

As further comparison, compositions comprising Base Oil (P3) and each ofpolymer D and polymer E were prepared following the same proceduredescribed above for the compositions according to the invention.

The compositions thus obtained were analysed by visual inspection andfound to be completely opalescent.

The compositions thus obtained were centrifuged for about 5 minutes inorder to improve their mixing. After this centrifugation, two phasesappeared showing a separation between the solid polymer and the BaseOil.

Due to this phase separation, the kinematic viscosities could not bemeasured and viscosity index could not be calculated.

Further analysis demonstrated that the two phases comprised the rawcomponents.

1. A composition (C) comprising at least one (per)fluoropolyether polymer (P) and at least one amorphous polymer (F), wherein said composition (C) is in the form of a solution.
 2. The composition according to claim 1, wherein said polymer (P) comprises a (per)fluoropolyether chain (R_(pf)) of formula: —(CFX)_(a)O(R_(f))(CFX′)_(b)— wherein a and b, equal or different from each other, are equal to or greater than 1; X and X′, equal or different from each other, are —F or —CF₃, provided that when a and/or b are greater than 1, X and X′ are —F; (R_(f)) comprises, preferably consists of, repeating units R^(∘), said repeating units being independently selected from the group consisting of: (i) —CFXO—, wherein X is F or CF₃; (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF₃, with the proviso that at least one of X is F; (iii) —(CF₂)_(j)—CFZ—O— wherein j is an integer from 0 to 3 and Z is a group of general formula —O—R_((f-a))-T, wherein R_((f-a)) is a fluoropolyoxyalkene chain comprising up to ten recurring units, said recurring units being selected from: —CFXO— and CF₂CFXO—, with each of each of X being independently F or CF₃ and T being a C₁-C₃ perfluoroalkyl group.
 3. The composition according to claim 2, wherein said chain (R_(f)) is selected from chains of formula: —[(CF₂CF₂O)_(b1)(CF₂O)_(b2)(CF(CF₃)O)_(b3)(CF₂CF(CF₃)O)_(b4)]—  (R_(f)-I) wherein: b1, b2, b3, b4, are independently integers ≥0 and are chosen so that the number average molecular weight is between 400 and 20,000; —[(CF₂CF₂O)_(c1)(CF₂O)_(c2)(CF₂(CF₂)_(cw)CF₂O)_(c3)]—  (R_(f)-II) wherein: cw=1 or 2; c1, c2, and c3 are independently integers ≥0 and are chosen so that the number average molecular weight is between 400 and 20,000; —[(CF₂CF(CF₃)O)_(d)]—  (R_(f)-III) wherein: d is an integer >0 and is chosen so that the number average molecular weight is between 400 and 20,000; —[(CF₂O)_(c2)(CF₂(CF₂)_(cw)CF₂O)_(c3)]—  (R_(f)-IV) wherein: cw=1 or 2; c2 and c3 are independently integers >0 and are chosen so that the number average molecular weight is between 400 and 20,000; —[(CF₂CF₂C(Hal*)₂O)_(e1)—(CF₂CF₂CH₂O)_(e2)—(CF₂CF₂CH(Hal*)O)_(e3)]—  (R_(f)-V) wherein: Hal*, equal or different at each occurrence, is a halogen selected from fluorine and chlorine atoms; e1, e2, and e3, equal to or different from each other, are independently integers ≥0 such that the (e1+e2+e3) sum is comprised between 2 and
 300. 4. The composition according to claim 3, wherein said chain (R_(f)) is selected from chains of formulae (R_(f)-VI-a) to (R_(f)-VI-c): —[(CF₂CF(CF₃)O)_(f1)—(CF₂O)_(f2)]—  (R_(f)-VI-a) wherein f1 and f2, are independently integers ≥0 and are chosen so that the number average molecular weight is between 400 and 20,000; —(CF(CF₃)CF₂O)_(n)—  (R_(f)-VI-b) wherein f3 is an integer higher than 0, and is chosen so that the number average molecular weight is between 400 and 20,000, preferably between 1,000 and 10,000; —(CF₂CF₂CF₂O)_(f4)—  (R_(f)-VI-c) wherein f4 is an integer higher than 0, and is chosen so that the number average molecular weight is between 400 and 20,000.
 5. The composition according to claim 1, wherein said polymer (F) is selected from the group consisting of amorphous polymers characterized by a glass transition temperature (T_(g)) in the range from −100° C. to 250° C., measured according to ASTM D3418.
 6. The composition according to claim 5, wherein said polymer (F) is selected from the group consisting of: styrene polymers and co-polymers; vinyl polymers and co-polymers; acrylic polymers and co-polymers; (per)fluoropolymers; polyesters; polyamideimide (PAI) and polyetherimide (PEI); polyethers; sulphur containing polymers; and polyurethane (TPU), fluorinated polyurethane and acrylonitrile polymers.
 7. The composition according to claim 6, wherein said polymer (F) is a perfluoropolymer.
 8. The composition according to claim 7, wherein said polymer (F) is a perfluoropolymer comprising recurring units derived from at least one perfluorinated monomer selected from the group consisting of: (A) cyclic monomers complying with one of the following formulae (A1) to (A3):

 wherein each of R_(f4), R_(f5), R_(f6), equal to or different from each other, is independently a fluorine atom or a C₁-C₆ perfluoroalkyl group, optionally comprising one or more oxygen atom;

 wherein n is 1 or 2;

 wherein n is 1 or 2; (B) C₂-C₈ perfluoroolefins, such as tetrafluoroethylene (TFE) and hexafluoropropene (HFP); (C) CF₂═CFOR_(f1), wherein Rn is selected from: (R_(f)i*) C₁-C₆ perfluoroalkyl group and (R_(f)i**) —CF₂OR_(f2) wherein t is an integer equal to 1 or 2 and R_(f2) is a linear or branched C₁-C₆ perfluoroalkyl group, a cyclic C₅-C₆ perfluoroalkyl group, or a linear or branched C₁-C₁₂ perfluorooxyalkyl group comprising one or more ether groups.
 9. The composition according to claim 8, wherein said polymer (F) comprises recurring units derived from tetrafluoroethylene (TFE) and from at least one perfluorinated monomer different from TFE [co-monomer (F)].
 10. The composition according to claim 9, wherein said at least one co-monomer (F) is selected from the group consisting of:

wherein each of R_(f4), R_(f5), R_(f6), equal to or different from each other, is independently a fluorine atom or a C₁-C₆ perfluoroalkyl group, optionally comprising one or more oxygen atom;

wherein n is 1 or 2;

wherein n is 1 or 2; and combinations thereof; or from the group consisting of: (C) CF₂═CFOR_(f1), wherein Rn is selected from: (R_(f1)*) —CF₃, —C₂F₅, and —C₃F₇, and combinations thereof; (R_(f1)**) —CF₂OR_(f2), wherein R_(f2) is a linear or branched C₁-C₆ perfluoroalkyl group, cyclic C₅-C₆ perfluoroalkyl group, or a linear or branched C₂-C₆ perfluoroxyalkyl group; and combinations thereof.
 11. The composition according to claim 8, wherein said polymer (F) essentially consists of recurring units of formula:

wherein each of R_(f4), R_(f5), R_(f6), equal to or different from each other, are as defined is independently a fluorine atom or a C₁-C₆ perfluoroalkyl group, optionally comprising one or more oxygen atom.
 12. The composition according to claim 8, wherein said polymer (F) comprises recurring units of formula: CF₂═CFO—CF₂O—CF₂CF₃ (MOVE1);  (D**i) CF₂═CFO—CF₂O—CF₂CF₂OCF₃ (MOVE2);  (D**ii) CF₂═CFO—CF₂O—CF(CF₃)OCF₃ (MOVE2a);  (D**iii) CF₂═CFO—CF₂O—CF₃ (MOVE3);  (D**iv) and combinations thereof.
 13. The composition according to claim 1, wherein said composition (C) comprises at least one polymer (P) in an amount higher than 50 wt. % and up to 99.99 wt. % based on the total weight of said composition (C).
 14. The composition according to claim 1, wherein said composition (C) comprises at least one polymer (F) in an amount of from 0.01 to less than 50 wt. % based on the total weight of said composition (C).
 15. A hydraulic fluid, damping media; lubricant or release agent comprising the composition (C) of claim
 1. 16. A method for increasing the viscosity of at least one polymer (P) as defined in claim 3, said method comprising contacting said at least one polymer (P) with at least one polymer (F), wherein polymer (F) is an amorphous polymers characterized by a glass transition temperature (T_(g)) in the range from −100° C. to 250° C., measured according to ASTM D3418.
 17. The composition according to claim 3, wherein: chain (R_(f)) is (R_(f)-I), b1 is 0, and b2, b3, b4, are independently integers ≥0 and are chosen so that the number average molecular weight is between 1,000 and 10,000, with the ratio b4/(b2+b3) being ≥1; or chain (R_(f)) is (R_(f)-II) and c1, c2, and c3 are independently integers >0 and are chosen so that the number average molecular weight is between 1,000 and 10,000, with the ratio c3/(c1+c2) being less than 0.2; or chain (R_(f)) is (R_(f)-III) and d is an integer >0 and is chosen so that the number average molecular weight is between 1,000 and 10,000; or chain (R_(f)) is (R_(f)-IV) and c2 and c3 are independently integers >0 and are chosen so that the number average molecular weight is between 1,000 and 10,000; with the ratio c3/c2 being less than 0.2; or chain (R_(f)) is (R_(f)-V) and each -Hal* is a fluorine atom.
 18. The composition according to claim 4, wherein chain (R_(f)) is (R_(f)-VI-a) and f1 and f2, are independently integers greater than 0 and are chosen so that the number average molecular weight is between 1,000 and 10,000, with the ratio f1/f2 being ≥1; or chain (R_(f)) is (R_(f)-VI-b) and f3 is an integer higher than 0, and is chosen so that the number average molecular weight is between 1,000 and 10,000; or chain (R_(f)) is (R_(f)-VI-c) and f4 is an integer higher than 0, and is chosen so that the number average molecular weight is between 1,000 and 10,000.
 19. The composition according to claim 1, wherein said composition (C) comprises at least one polymer (P) in an amount from 60 wt. % to about 99.95 wt. %, based on the total weight of said composition (C).
 20. The composition according to claim 1, wherein said composition (C) comprises at least one polymer (F) in an amount of from 0.05 to 40 wt. %, based on the total weight of said composition (C). 